Process for preparing carrier-borne transition metal catalysts

ABSTRACT

A process for preparing a supported transition metal catalyst comprising a particulate organic or inorganic support material, a transition metal complex and a compound capable of forming metallocenium ions comprises the following process steps: 
     a) contacting a solution of a compound capable of forming metallocenium ions with a second solvent in which this compound is only sparingly soluble, in the presence of the support material, 
     b) removing at least part of the solvent from the support material and 
     c) contacting a solution of a mixture of a compound capable of forming metallocenium ions and a transition metal complex with a second solvent in which this mixture is only sparingly soluble, in the presence of the support material obtained as described in a) and b).

The present invention relates to a process for preparing a supportedtransition metal catalyst comprising a particulate organic or inorganicsupport material, a transition metal complex and a compound capable offorming metallocenium ions.

The present invention also relates to a supported catalyst obtainable bythis process, a process for preparing polymers by means of this catalystand the use of these polymers for producing fibers, films and moldings.

Supported transition metal catalysts have been known for a long time andare, for example, used for olefin polymerization. The activity andproductivity of these catalysts depends significantly on their processof preparation. The selection of the loading parameters generallyattempts to achieve a sufficiently strong binding of the catalyst andpossibly the cocatalysts to the support and also as homogeneous aspossible a distribution of the active components on the support.

WO 94/28034 describes the preparation of a supported catalyst for olefinpolymerization, where a metallocene complex together with an aluminoxaneor methylaluminoxane in a liquid hydrocarbon is brought into contactwith an inert support, typically silica gel, and the solvent issubsequently removed by distillation.

EP-A1-295 312 describes various processes for preparing supported olefinpolymerization catalysts. A feature common to these processes is that asolution of an aluminoxane is brought into contact with a second solventin which the aluminoxane is insoluble in the presence of a particulateorganic or inorganic support, resulting in precipitation of thealuminoxane onto the support. In the various embodiments, first thealuminoxane and then a metallocene complex are precipitated stepwiseonto the support or else a mixture of aluminoxane and metallocenecomplex is precipitated simultaneously.

However, the preparative methods described lead to supported catalystswhich still leave something to be desired in terms of their activity andproductivity.

It is an object of the present invention to find a process for preparingsupported transition metal catalysts which leads to catalysts of higherproductivity.

We have found that this object is achieved by a process for preparing asupported transition metal catalyst comprising a particulate organic orinorganic support material, a transition metal complex and a compoundcapable of forming metallocenium ions, which comprises the followingprocess steps:

a) contacting a solution of a compound capable of forming metalloceniumions with a second solvent in which this compound is only sparinglysoluble, in the presence of the support material,

b) removing at least part of the solvent from the support material and

c) contacting a solution of a mixture of a compound capable of formingmetallocenium ions and a transition metal complex with a second solventin which this mixture is only sparingly soluble, in the presence of thesupport material obtained as described in a) and b).

Furthermore, we have found a supported catalyst obtainable by thisprocess, a process for preparing polymers by means of this catalyst andthe use of these polymers for producing fibers, films and moldings.

Examples of suitable particulate organic or inorganic support materialare polyolefins such as polyethylene, polypropylene, poly-1-butene andpolymethyl-1-pentene and copolymers with the monomers on which thesepolymers are based, also polyesters, polyamides, polyvinyl chloride,polyacrylates and polymethacrylates and polystyrene. However, preferenceis given to inorganic support materials such as porous oxides, eg. SiO₂,Al₂ O₃, MgO, ZrO₂, TiO₂, B₂O₃, CaO, ZnO. Metal halides such as MgCl₂ arealso suitable as supports. The support materials preferably have aparticle diameter of from 1 to 300 μm, in particular from 30 to 70 μm.Examples of particularly preferred supports are silica gels, preferablythose of the formula SiO₂·a Al₂O₃, where a is a number in the range from0 to 2, preferably from 0 to 0.5; these are thus aluminosilicates orsilicon dioxide. Such products are commercially available, eg. SilicaGel 332 from Grace.

Particularly suitable silica gels are those which have voids andchannels whose macroscopic proportion by volume in the total particle isin the range from 5 to 30%. Preference is given to those silica gelsupports which have a mean particle diameter of from 5 to 200 μm and amean particle diameter of the primary particles of from 1 to 20 μm, inparticular from 1 to 10 μm. The primary articles [sic] here are porous,granular particles. The primary particles have pores having a diameterof, in particular, from 1 to 1000 Ångström. Furthermore, the inorganicoxides to be used additionally have voids and channels having a diameterof from 1 to 20 μm. These silica gels also have, in particular, a porevolume of from 0.1 to 10 cm³/g, preferably from 1.0 to 5.0 cm³/g, and aspecific surface area of from 10 to 1000 m²/g. Such products arecommercially available, e.g. Sylopol 2101 (from Grace), ES 70X (fromCrosfield) or MS 3040 (from PQ Corporation). Further characteristics ofsuch silica gels are described in the previous German Patent Application19 623 225.2, whose contents are incorporated by reference into thepresent document.

Examples of suitable transition metal complexes are metal complexescontaining metallocene ligands or other organic ligands such asβ-diketiminate or azaallyl ligands, as are described, for example, in J.Organomet. Chem. 500 (1995), 203-217, in WO 95/33776 and also in theprevious German Patent Application 19 616 523.7. Particularly suitabletransition metal complexes for use in the process of the presentinvention are metallocene complexes of elements of the 4th and 5thtransition groups of the Periodic Table. Particularly suitabletransition metal complexes are, furthermore, those containingbenzindenyl ligands. These benzindenyl ligands can be substituted orunsubstituted.

Suitable metallocene complexes are in particular those of the generalformula III

where the substituents have the following meanings:

M is titanium, zirconium, hafnium, vanadium, niobium or tantalum,

X is fluorine, chlorine, bromine, iodine, hydrogen, C₁-C₁₀-alkyl,C₆-C₁₅-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkylradical and from 6 to 20 carbon atoms in the aryl radical, —OR⁷ or—NR⁷R⁸,

where

R⁷ and R⁸ are C₁-C₁₀-alkyl, C₆-C₁₅-aryl, alkylaryl, arylalkyl,fluoroalkyl or fluoroaryl each having from 1 to 10 carbon atoms in thealkyl radical and from 6 to 20 carbon atoms in the aryl radical,

R² to R⁶ are hydrogen, C₁-C₁₀-alkyl, 5- to 7-membered cycloalkyl whichmay in turn bear a C₁-C₁₀-alkyl group as substituent, C₆-C₁₅-aryl orarylalkyl, where two adjacent radicals may also together form asaturated or unsaturated cyclic group having from 4 to 15 carbon atoms,or Si(R⁹)₃ where

R⁹ is C₁-C₁₀-alkyl, C₃-C₁₀-cycloalkyl or C₆-C₁₅-aryl,

where the radicals

R¹⁰ to R¹⁴ are hydrogen, C₁-C₁₀-alkyl, 5- to 7-membered cycloalkyl whichmay in turn bear a C₁-C₁₀-alkyl group as substituent, C₆-C₁₅-aryl orarylalkyl and where two adjacent radicals may also together form asaturated or unsaturated cyclic group having from 4 to 15 carbon atoms,or Si(R¹⁵)₃ where

R¹⁵ is C₁-C₁₀-alkyl, C₆-C₁₅-aryl or C₃-C₁₀-cycloalkyl,

or where the radicals R⁵ and Z together form a group —R¹⁶—A—, where

═BR¹⁷, ═AlR¹⁷, —Ge—, —Sn—, —O—, —S—, ═SO, ═SO₂, ═NR¹⁷, ═CO, ═PR¹⁷ or═P(O)R¹⁷,

where

R¹⁷, R¹⁸ and R¹⁹ are identical or different and are hydrogen, halogen,C₁-C₁₀-alkyl, C₁-C₁₀-fluoroalkyl, C₆-C₁₀-fluoroaryl, C₆-C₁₀-aryl,C₁-C₁₀-alkoxy, C₂-C₁₀-alkenyl, C₇-C₄₀-arylalkyl, C₈-C₄₀-arylalkenyl orC₇-C₄₀-alkylaryl or two adjacent radicals together with the atomsconnecting them form a ring, and

M² is silicon, germanium or tin,

R²⁰ is C₁-C₁₀-alkyl, C₆-C₁₅-aryl, C₃-C₁₀-cycloalkyl, alkylaryl orSi(R²¹)₃,

R²¹ is hydrogen, C₁-C₁₀-alkyl, C₆-C₁₅-aryl which may in turn besubstituted by C₁--C₄-alkyl groups, or C₃-C₁₀-cycloalkyl

or where the radicals R⁵ and R¹³ together form a group —R¹⁶—.

Among the metallocene complexes of the general formula III, preferenceis given to

Particular preference is given to those transition metal complexes whichcontain two aromatic ring systems bridged to one another as ligands, ie.in particular the transition metal complexes of the general formulaeIIIb and IIIc.

The radicals X can be identical or different, preferably identical.

Among the compounds of the formula IIIa, particular preference is givento those in which

M is titanium, zirconium or hafnium,

X is chlorine, C₁-C₄-alkyl or phenyl and

R² to R⁶ is hydrogen or C₁-C₄-alkyl.

Among the compounds of the formula IIIb, preference is given to those inwhich

M is titanium, zirconium or hafnium,

X is chlorine, C₁-C₄-alkyl or phenyl,

R² to R⁶ are hydrogen, C₁-C₄-alkyl or Si(R⁹)₃,

R¹⁰ to R¹⁴ are hydrogen, C₁-C₄-alkyl or Si(R¹⁵)₃.

Particularly suitable are the compounds of the formula IIIb in which thecyclopentadienyl radicals are identical.

Examples of particularly suitable compounds are:

bis(cyclopentadienyl)zirconium dichloride,

bis(pentamethylcyclopentadienyl)zirconium dichloride,

bis(methylcyclopentadienyl)zirconium dichloride,

bis(ethylcyclopentadienyl)zirconium dichloride,

bis(n-butylcyclopentadienyl)zirconium dichloride and

bis(trimethylsilylcyclopentadienyl)zirconium dichloride

and also the corresponding dimethylzirconium compounds.

Particularly suitable compounds of the formula IIIc are those in which

R² and R¹⁰ are identical and are hydrogen or C₁-C_(10-alkyl,)

R⁶ and R¹⁴ are identical and are hydrogen, methyl, ethyl, iso-propyl ortert-butyl,

R³, R⁴, R¹¹and R¹² have the meanings

R⁴ and R¹² are C₁-C₄-alkyl,

R³ and R¹¹ are hydrogen or two adjacent radicals R³ and R⁴ or R¹¹ andR¹² together form cyclic groups having from 4 to 12 carbon atoms,

M is titanium, zirconium or hafnium and

X chlorine, C₁-C₄-alkyl or phenyl.

Examples of particularly suitable complexes are:

dimethylsilanediylbis(cyclopentadienyl)zirconium dichloride,

dimethylsilanediylbis(indenyl)zirconium dichloride,

dimethylsilanediylbis(tetrahydroindenyl)zirconium dichloride,

ethylenebis(cyclopentadienyl)zirconium dichloride,

ethylenebis(indenyl)zirconium dichloride,

ethylenebis(tetrahydroindenyl)zirconium dichloride,

tetramethylethylene-9-fluorenylcyclopentadienylzirconium dichloride,

dimethylsilanediylbis(3-tert-butyl-5-methylcyclopentadienyl) zirconiumdichloride,

dimethylsilanediylbis(3-tert-butyl-5-ethylcyclopentadienyl) zirconiumdichloride,

dimethylsilanediylbis(2-methylindenyl)zirconium dichloride,

dimethylsilanediylbis(2-isopropylindenyl)zirconium dichloride,

dimethylsilanediylbis(2-tert-butylindenyl)zirconium dichloride,

diethylsilanediylbis(2-methylindenyl)zirconium dibromide,

dimethylsilanediylbis(3-methyl-5-methylcyclopentadienyl) zirconiumdichloride,

dimethylsilanediylbis(3-ethyl-5-isopropylcyclopentadienyl)zirconiumdichloride,

dimethylsilanediylbis(2-methylindenyl)zirconium dichloride,

dimethylsilanediylbis(2-methylbenzindenyl)zirconium dichloride

dimethylsilanediylbis(2-ethylbenzindenyl)zirconium dichloride,

methylphenylsilanediylbis(2-ethylbenzindenyl)zirconium dichloride,

methylphenylsilanediylbis(2-methylbenzindenyl)zirconium dichloride,

diphenylsilanediylbis(2-methylbenzindenyl)zirconium dichloride,

diphenylsilanediylbis(2-ethylbenzindenyl)zirconium dichloride, anddmethylsilanediylbis(2-methylindenyl)hafnium dichloride and also thecorresponding dimethylzirconium compounds.

Particularly suitable compounds of the general formula IIId are those inwhich

M is titanium or zirconium,

X if chlorine, C₁-C₄-alkyl or phenyl,

and

R² to R⁴ and R⁶ are hydrogen, C₁-C₁₀-alkyl, C₃-C₁₀-cycloalkyl,

C₆-C₁₅-aryl or Si(R⁹)₃, or two adjacent radicals form a cyclic grouphaving from 4 to 12 carbon atoms.

Such complexes can be synthesized by methods known per se, with thereaction of the corresponding substituted, cyclic hydrocarbon anionswith halides of titanium, zirconium, hafnium, vanadium, niobium ortantalum being preferred.

Examples of corresponding preparative methods are described in, interalia, Journal of Organometallic Chemistry, 369 (1989), 359-370.

It is also possible to use mixtures of different metallocene complexes.

As a further component, the catalyst prepared by the process of thepresent invention comprises a compound capable of forming metalloceniumions.

Suitable compounds capable of forming metallocenium ions are strong,uncharged Lewis acids, ionic compounds having Lewis-acid cations andionic compounds having a Brönsted acid as cation.

As strong, uncharged Lewis acids, preference is given to compounds ofthe general formula IV

M³X¹X²X³  IV

where

M³ is an element of main group III of the Periodic Table, in particularB, Al or Ga, preferably B,

X¹, X² and X³ are hydrogen, C₁-C₁₀-alkyl, C₆-C₁₅-aryl, alkylaryl,arylalkyl, haloalkyl or haloaryl each having from 1 to 10 carbon atomsin the alkyl radical and from 6 to 20 carbon atoms in the aryl radicalor fluorine, chlorine, bromine or iodine, in particular haloaryls,preferably pentafluorophenyl.

Particular preference is given to compounds of the general formula IV,in which X¹, X² and X³ are identical, preferablytris(pentafluorophenyl)borane.

Suitable ionic compounds having Lewis-acid cations are compoundsontaining cations of the general formula V

[(Y^(a+))Q₁Q₂ . . . Q_(z)]^(d+)  V,

where

Y is an element of main groups I to VI or transition groups I to VIII ofthe Periodic Table,

Q_(l) to Q_(Z) are singly negatively charged groups such asC₁-C₂₈-alkyl, C₆-C₁₅-aryl, alkylaryl, arylalkyl, haloalkyl, haloaryleach having from 6 to 20 carbon atoms in the aryl radical and from 1 to28 carbon atoms in the alkyl radical, C₁-C₁₀-cycloalkyl which may besubstituted by C₁-C₁₀-alkyl groups, halogen, C₁-C₂₈-alkoxy,C₆-C₁₅-aryloxy, silyl or mercaptyl,

a is an integer from 1 to 6,

z is an integer from 0 to 5

d is the difference a-z but is greater than or equal to 1.

Particularly suitable cations are carbonium cations, oxonium cations andsulfonium cations and also cationic transition metal complexes.Particular mention may be made of the triphenylmethyl cation, the silvercation and the 1,1′-dimethylferrocenyl cation. They preferably havenon-coordinating counterions, in particular boron compounds as are alsomentioned in WO 91/09882, preferably tetrakis(pentafluorophenyl)borate.

Ionic compounds having Bronsted acids as cations and preferably likewisenon-coordinating counterions are mentioned in WO 91/09882, the preferredcation being N,N-dimethylanilinium.

Particularly suitable compounds capable of forming metallocenium ionsare open-chain or cyclic aluminoxane compounds of the general formula Ior II

where R¹ is C₁-C₄-alkyl, preferably methyl or ethyl, and m is an integerfrom 5 to 30, preferably from 10 to 25.

The preparation of these oligomeric aluminoxane compounds is customarilycarried out by reacting a solution of trialkylaluminum with water and isdescribed, for example, in EP-A 284 708 and U.S. Pat. No. 4,794,096.

The resulting oligomeric aluminoxane compounds are generally in the formof mixtures of linear and cyclic chain molecules of different lengths,so that m is to be regarded as a mean. The aluminoxane compounds canalso be present in admixture with other metal alkyls, preferably withaluminum alkyls.

As compounds capable of forming metallocenium ions, it is also possibleto use aryloxyaluminoxanes as described in U.S. Pat. No. 5,391,793,aminoaluminoxanes, as described in U.S. Pat. No. 5,371,260,aminoaluminoxane hydrochlorides, as described in EP-A 633 264,siloxyaluminoxanes, as described in EP-A 621 279, or mixtures thereof.

The first process step a) for the preparation according to the presentinvention of the supported transition metal catalysts comprisescontacting a solution of a compound capable of forming metalloceniumions with a second solvent in which this compound is only sparinglysoluble, in the presence of the support material. For this purpose, thecompound capable of forming metallocenium ions is first dissolved in afirst solvent in which it is readily soluble. Suitable solvents for manycompounds capable of forming metallocenium ions, particularly for thealuminoxane compounds of the formulae I and II, are, for example,aromatic solvents such as benzene, toluene, ethylbenzene, xylene orchlorobenzene and also chlorinated hydrocarbons such as dichloroethaneor methylene chloride.

As second solvent in which the compound capable of forming metalloceniumions is only sparingly soluble, suitable solvents are especially linearor branched aliphatic hydrocarbons such as pentane, hexane, heptane,octane, decane, dodecane, in particular isododecane. It is also possibleto use industrial mixtures of various hydrocarbons of this type, eg.kerosine and the isododecane mentioned. Also suitable as second solventare cycloaliphatic solvents such as cyclohexane and norbornane. In thiscontext, sparingly soluble means that out of the given concentrations ofthe compound capable of forming metallocenium ions the major part ofthis compound can be precipitated by the solvent.

The contacting can be carried out in various ways. For example, thesolution of the compound capable of forming metallocenium ions can beinitially charged and admixed with a suspension of the support materialin the second solvent or vice versa. It is also possible to initiallycharge a suspension of the support material in the first solvent or in asolution of the compound capable of forming metallocenium ions and admixthis with the second solvent. A particularly useful variant is tosuspend the support material in the second solvent and to slowly add thesolution of the compound capable of forming metallocenium ions to thissuspension; the suspension should be stirred continuously during thisprocedure.

For process step a), it is advantageous to adhere to the followingweight ratios:

The ratio of compound capable of forming metallocenium ions to thesupport material should be as high as possible in order to achieve ashigh as possible a loading of the support. It is preferably from 1:1 to0.05:1, particularly preferably from 0.8:1 to 0.3:1.

The ratio of compound capable of forming metallocenium ions to the firstsolvent should where possible be as great as the solubility permits,thus generally from 0.5:1 to 0.01:1, particularly preferably from 0.3:1to 0.1:1.

The ratio of the first solvent to the second solvent should be as low aspossible in order to achieve as effective as possible a precipitation ofthe compound capable of forming metallocenium ions onto the support.Preference is given to a weight ratio of from 1:1 to 0.05:1,particularly preferably from 0.5:1 to 0.1:1.

In the subsequent process step b), at least part of the solvent isremoved from the support material modified as described in a). This canbe carried out, for example, by distillation, preferably by fractionaldistillation. When solvent is removed by distillation, it is advisableto select the solvent pair such that the first solvent has a lowerboiling point, preferably a boiling point more than 20° C. lower, thanthe second solvent. In this way, the major part of the first solvent canbe removed from the suspension, thus achieving a more effectiveprecipitation of the catalyst component in step c).

A mechanical separation of the suspension, for example by filtration,has been found to be even more useful than the removal of the solvent bydistillation. In this way, nonvolatile unbound constituents of thesolution of the compound capable of forming metallocenium ions can alsobe removed from the support material. An embodiment of the process ofthe present invention in which the support material is filtered off andthen washed first with the first solvent or another solvent in which thecompound capable of forming metallocenium ions is readily soluble andsubsequently with the second solvent has been found to be particularlyadvantageous since catalysts of particularly high productivity can beprepared in this way.

This washing step is preferably carried out using from 5 to 40 parts byvolume of the respective solvent, particularly preferably from 10 to 20parts by volume, in each case based on the volume of the supportmaterial. Repeated washing with the corresponding solvents has also beenfound to be advantageous.

The step c) of the process of the present invention comprises loadingthe support with the actual catalyst complex. Suitable ways of carryingout step c) are the same as those mentioned for step a). Here too, ithas been found to be advantageous to initially charge a suspension ofthe support material in the second solvent and to slowly add thesolution of a mixture of the compound capable of forming metalloceniumions and the transition metal complex in the first solvent to thissuspension, preferably whilst stirring continually.

After the addition of the solution of the mixture of the compoundcapable of forming metallocenium ions and the transition metal complex,it can be advantageous to achieve complete precipitation by distillativeremoval of the first solvent which in this case has to have a lowerboiling point than the second solvent. This procedure is particularlyadvantageous when a large amount of the first solvent has had to be usedfor solubility reasons.

The mixture of compound capable of forming metallocenium ions andtransition metal complex preferably contains these two components in aweight ratio of from 40:1 to 3:1, particularly preferably from 20:1 to5:1.

The solution of the mixture should be as concentrated as possible. Thissolution preferably contains from 5 to 50% by weight of the mixture,particularly preferably from 20 to 30% by weight.

For the other proportions by volume and weight, the ratios specified forprocess step a) apply.

The process temperature for the loading steps depends, inter alia, onthe stability of the compound capable of forming metallocenium ions andof the transition metal complex. The temperature of the suspension ofthe support should preferably be low while the temperature of thesolution of the active components in process steps a) and c) should behigher, although a uniform process temperature also leads to goodresults. The process temperature is generally from −10 to +60° C.,preferably from +10 to +40° C., particularly preferably from 20 to 30°C.

The pressure has virtually no influence on the process result, althougha reduced pressure can be advantageous in the distillation in processstep c).

The multistage process of the present invention for preparing asupported transition metal catalyst leads to catalysts having veryhomogeneously distributed active components and high loadings. Theseadvantages result from the combination of the process steps a), b) andc). In step a), a high loading of the support with the compound capableof forming metallocenium ions is achieved. Step b) removes constituentswhich interfere in the subsequent step c). By means of the prereactionof the transition metal complex with the compound capable of formingmetallocenium ions, step c) effects the formation of an active catalystcomplex and an increase in the solubility of the transition metalcomplex, thus making possible a higher and more homogeneous loading ofthe support. The increase in the solubility is particularly useful inthe case of sparingly soluble complexes such as the transition metalcomplexes having two aromatic ring systems bridged to one another.However, without the pretreatment of the support in accordance withprocess step a), process step c) leads to unsatisfactory results.

According to the present invention, the supported transition metalcatalyst described here is particularly suitable for processes forpreparing polymers of C₂-C₁₂-alk-1-enes at from −50 to 300° C. andpressures of from 0.5 to 3000 bar.

Among the C₂-C₁₂-alk-1-enes used in the process of the present inventionfor preparing polymers, preference is given to ethylene, propene,1-butene, 1-pentene, 4-methylpent-1-ene, 1-hexene, 1-heptene or1-octene, and also mixtures of these. Particular preference is given tohomopolymers or copolymers of propene, with the propene in thecopolymers being at least 50 mol %. Preferred copolymers of propene arethose containing ethylene or 1-butene or a mixture thereof as furthermonomers.

The process of the present invention for preparing polymers is carriedout at from −50 to 300° C., preferably from 0 to 150° C. and atpressures in the range from 0.5 to 3000 bar, preferably in the rangefrom 1 to 80 bar.

The polymerization can be carried out in solution, in suspension, inliquid monomers or in the gas phase. The polymerization is preferablycarried out in liquid monomers or in the gas phase, with the stirred gasphase being preferred.

The process can be carried out continuously or batchwise. Suitablereactors are, inter alia, continuous stirred vessels, with it also beingpossible to use, if desired, a series of stirred vessels connected inseries (reactor cascade).

The polymerization process of the present invention can be carried outreadily on an industrial scale and gives good polymer morphology,uniform polymer chain lengths, no deposit formation, no agglomerateformation and good productivity.

A preferred embodiment of the polymerization process of the presentinvention comprises polymerization in the presence of hydrogen asmolecular weight regulator. The catalyst system of the present inventionresponds to even small amounts of hydrogen to give a pronouncedproductivity increase. The proportion of hydrogen, eg. in a gas-phasepolymerization, is preferably from 0.01 to 1.2% by volume, particularlypreferably from 0.05 to 0.9% by volume, based on the total volume of thepolymerization gas mixture.

The polymers obtained by the polymerization process of the presentinvention are well suited, for example, to the production of fibers,films and moldings.

EXAMPLES Example 1

1.1 Preparation of the catalyst

20 g of silica gel SG 332 (manufactured by Grace, Worms) were partiallydehydrated under reduced pressure at 180° C. for 8 hours, suspended in170 ml of pentane and subsequently 160 ml of 1.53M methylaluminoxane(MAO) in toluene (manufactured by Witco, Bergkamen) were added dropwiseover a period of 4 hours. After 12 hours at 25° C., the supernatantcolorless solution was decanted off and the MAO-laden support was washedwith 2×50 ml of toluene and subsequently with 2×50 ml of pentane. TheMAO-laden silica gel was resuspended in 150 ml of pentane and admixedover a period of 4 hours with a solution of 115 mg ofrac-bis[3,3′-(2-methyl-benzo[e]indenyl)]dimethylsilanediylzirconiumdichloride in 30.6 ml of 1.53M MAO (toluene solution). After 1 hour, thesupported catalyst was isolated by filtration, washed with 2×50 ml ofpentane and dried in a stream of N₂ at 25° C.

Yield: 29 g

1.2 Polymerization

50 g of polypropylene powder and 10 ml of triisobutylaluminum (2M inheptane) were placed one after the other in a dry 10 l autoclave whichhad been flushed with nitrogen and was stirred for 15 minutes.Subsequently, 510 mg of supported catalyst were introduced into thereactor in a countercurrent of nitrogen, the autoclave was closed andcharged with 1.5 l of liquid propylene at 25° C. and a stirrer speed of350 rpm. After prepolymerization for 30 minutes, the temperature wasincreased stepwise to 65° C., with the internal pressure being increasedstepwise by means of automatic pressure regulation to the final pressureof 25 bar. Polymerization was then carried out in the gas phase at 65°C. for 60 minutes with automatic propylene gas pressure regulation (25bar). After polymerization was complete, the autoclave was depressurizedto atmospheric pressure over a period of 10 minutes and the resultingpolymer was discharged in a stream of nitrogen. This gave 815 g ofpolypropylene powder, corresponding to a productivity of 1500 g of PP/gof catalyst/h. The associated catalyst and polymer data are listed inTables 1 and 2.

Example 2

The preparation of the catalyst was carried out using a method similarto Example 1. The MAO loading of the partially dehydrated silica gel wascarried out in the manner described above. For the metallocene loading,288 mg ofrac-bis[3,3′-(2-methylbenzo[e]-indenyl)]dimethylsilanediylzirconiumdichloride in 65 ml of 1.53M MAO (toluene solution) were used. The yieldwas 30.1 g.

In the polymerization of propylene (carried out similarly to thepolymerization of Example 1), 413 mg of supported catalyst gave 1065 gof polymer powder, corresponding to a productivity of 2450 g of PP/g ofcatalyst/h. The associated catalyst and polymer data are listed inTables 1 and 2.

Example 3

The preparation of the catalyst was carried out using a method similarto Example 1. The MAO loading of the partially dehydrated silica gel wascarried out in the manner described above. For the metallocene loading,576 mg ofrac-bis[3,3′-(2-methylbenzo[e]-indenyl)]dimethylsilanediylzirconiumdichloride in 130 ml of 1.53M MAO (toluene solution) were used. Theyield was 32.4 g.

In the polymerization of propylene (carried out similarly to thepolymerization of Example 1), 305 mg of supported catalyst gave 1180 gof polymer powder, corresponding to a productivity of 3700 g of PP/g ofcatalyst/h. The associated catalyst and polymer data are listed inTables 1 and 2.

Example 4

The preparation of the catalyst was carried out using a method similarto Example 1. The MAO loading of the partially dehydrated silica gel wascarried out in the manner described above. For the metallocene loading,1152 mg ofrac-bis[3,3′-(2-methylbenzo[e]-indenyl)]dimethylsilanediylzirconiumdichloride in 260 ml of 1.53M MAO (toluene solution) were used. Theyield was 32.9 g.

In the polymerization of propylene (carried out similarly to thepolymerization of Example 1), 227 mg of supported catalyst gave 1180 gof polymer powder, corresponding to a productivity of 4950 g of PP/g ofcatalyst/h. The associated catalyst and polymer data are listed inTables 1 and 2.

Example 5

The preparation of the catalyst was carried out using a method similarto Example 1. The MAO loading of the partially dehydrated silica gel wascarried out in the manner described above. For the metallocene loading,2304 mg ofrac-bis[3,3′-(2-methylbenzo[e]-indenyl)]dimethylsilanediylzirconiumdichloride in 520 ml of 1.53M MAO (toluene solution) were used. Theyield was 33.4 g.

In the polymerization of propylene (carried out similarly to thepolymerization of Example 1), 108 mg of supported catalyst gave 695 g ofpolymer powder, corresponding to a productivity of 4950 g of PP/g ofcatalyst/h. The associated catalyst and polymer data are listed inTables 1 and 2.

Example 6

6.1 Preparation of the catalyst

20 g of silica gel SG 332 were partially dehydrated under 45 reducedpressure at 180° C. for 8 hours, suspended in 200 ml of iso-dodecane and160 ml of 1.53M MAO (toluene solution) was then slowly added dropwise at0° C. over a period of 4 hours.

After 12 hours at 0° C., the supernatant colorless solution was filteredoff and the MAO-laden support was washed with 2×50 ml of toluene andsubsequently with 2×50 ml of pentane. Drying at 25° C. in a stream of N₂gave 28.2 g of MAO-laden silica gel.

5.0 g of the MAO-laden silica gel thus prepared was suspended in 200 mlof iso-dodecane and admixed at 0° C. with a solution of 288 mg ofbis[3,3′-(2-methylbenzo[e]indenyl)]dimethylsilanediylzirconiumdichloride in 65 ml of 1.53M MAO (toluene solution) over a period of 4hours. After 1 hour, the supported catalyst was isolated by filtration,washed with 2×25 ml of pentane and dried at 25° C. in a stream of N₂.The yield was 5.6 g.

6.2 Polymerization

The polymerization was carried out using a method similar to Example1.2. In the polymerization of propylene, 198 mg of supported catalystgave 1050 g of polymer powder, corresponding to a productivity of 5050 gof PP/g of catalyst/h. The associated polymer data are listed in Table3.

7.1 Preparation of the catalyst

160 ml of 1.53M MAO (toluene solution) was reduced to 60 ml at 25° C. ina high vacuum (100 ml distilled off). The concentrated MAO/toluenesolution was slowly added dropwise at 0° C. to a suspension of 20 g ofsilica gel SG 332 (partially dehydrated at 180° C. under reducedpressure for 8 hours) and 200 ml of iso-dodecane over a period of 4hours. After 12 hours at 0° C., the supernatant colorless solution wasfiltered off and the MAO-laden support was washed with 2×50 ml oftoluene and subsequently with 2×50 ml of pentane. Drying at 25° C. in astream of N₂ gave 33.8 g of MAO-laden silica gel.

A solution of 288 mg ofrac-bis[3,3′-(2-methylbenzo[e]-indenyl)]dimethylsilanediylzirconiumdichloride in 65 ml of 1.53M MAO/toluene solution was reduced to avolume of 30 ml at 25° C. in a high vacuum. Subsequently, theconcentrated MAO/metallocene solution was slowly added dropwise at 25°C. to a suspension of 5.0 g of the MAO-laden silica gel prepared abovein 200 ml of iso-dodecane over a period of 4 hours. After 1 hour, thesupported catalyst was isolated by filtration, washed with 2×25 ml ofpentane and dried at 25° C. in a stream of N₂. The yield was 6.1 g.

7.2 Polymerization

The polymerization was carried out using a method similar to Example1.2. In the polymerization of propylene, 142 mg of supported catalystgave 860 g of polymer powder, corresponding to a productivity of 5700 gof PP/g of catalyst/h. The associated polymer data are listed in Table3.

Example 8

5 g of silica gel SG 332 were partially dehydrated at 180° C. underreduced pressure for 8 hours, suspended in 50 ml of iso-dodecane and 160ml of 1.53M MAO solution in toluene was then slowly added dropwise overa period of 4 hours. After 12 hours at 25° C., the supernatant colorlesssolution was decanted off and the MAO-laden support was washed with 2×10ml of toluene. Subsequently, the MAO-laden silica gel was resuspended in100 ml of iso-dodecane and admixed at 25° C. while stirring with half ofa solution of 288 mg ofrac-bis[3,3′-(2-methylbenzo[e]indenyl)]dimethylsilanediylzirconiumdichloride in 65 ml of 1.53M MAO (toluene solution) over a period of 2hours. After 0.5 hour, the solvent was removed by means of filtrationand the solid was again taken up in 100 ml of iso-dodecane. Theremaining amount of therac-bis[3,3′-(2-methylbenzo[e]indenyl)]dimethylsilanediylzirconiumdichloride/MAO solution was then added dropwise over a further period of2 hours. After addition was complete, the suspension was stirred at 25°C. for a further 0.5 hour and the solid was then filtered off. Washingwith 2×20 ml of pentane gave 8.5 g of catalyst.

The polymerization was carried out using a method similar to Example1.2. In the polymerization of propylene, 213 mg of supported catalystgave 1120 g of polymer powder, corresponding to a productivity of 5000 gof PP/g of catalyst/h. The associated polymer data are listed in Table3.

Example 9

5 g of silica gel SG 332 were partially dehydrated at 180° C. underreduced pressure for 8 hours, suspended in 50 ml of pentane and aquarter of 160 ml of 1.53M MAO (toluene solution) was then slowly addeddropwise at 25° C. over a period of 1 hour. After 3 hours, the solid wasfiltered off and resuspended in 50 ml of pentane. The second quarter ofthe MAO solution used above was then added dropwise (1 hour addition, 3hours further stirring). After filtering again and resuspending thesolid in 50 ml of pentane, the MAO loading was continued with a further40 ml of MAO solution (1 hour addition, 3 hours further stirring). Afterfiltration and resuspension of the solid in 50 ml of pentane, the last40 ml of MAO solution were slowly added at 25° C. (1 hour). After 12hours at 25° C., the supernatant colorless solution was filtered off andthe MAO-laden support was washed with 2×10 ml of toluene. Subsequently,the MAO-laden silica gel was resuspended in 100 ml of iso-dodecane andadmixed at 25° C. while stirring with half of a solution of 288 mg ofrac-bis[3,3′-(2-methylbenzo[e]indenyl)]dimethylsilanediylzirconiumdichloride in 65 ml of 1.53M MAO (toluene solution) over a period of 2hours. After 0.5 hour, all the solvent was removed by means offiltration and the solid was again taken up in 100 ml of iso-dodecane.The remaining part of therac-bis[3,3′-(2-methylbenzo[e]indenyl)]dimethylsilanediylzirconiumdichloride/MAO solution was then added dropwise over a further period of2 hours. After addition was complete, the suspension was stirred at 25°C. for a further 0.5 hour and the solid was then filtered off. Washingwith 2×20 ml of pentane gave 8.9 g of catalyst.

The polymerization was carried out using a method similar to Example1.2. In the polymerization of propylene 197 mg of supported catalystgave 1095 g of polymer powder, corresponding to a productivity of 5300 gof PP/g of catalyst/h. The associated polymer data are listed in Table3.

Example 10

10.1 Preparation of the catalyst

20 g of silica gel SG 332 were partially dehydrated at 180° C. underreduced pressure for 8 hours, suspended in 200 ml of iso-decane and 160ml of 1.53M MAO (toluene solution) were then slowly added dropwise at25° C. over a period of 4 hours. After 12 hours at 25° C., thesupernatant colorless solution was filtered off and the MAO-ladensupport was washed with 2×10 ml of toluene and subsequently with 2×50 mlof pentane. Drying at 25° C. in a stream of N₂ gave 28.1 g ofMAO-deactivated silica gel. A solution of 576 mg ofrac-bis-[3,3′-(2-methylbenzo[e]indenyl)]dimethylsilanediylzirconiumdichloride in 130 ml of 1.53M MAO/toluene solution was reduced to avolume of 50 ml at 25° C. in a high vacuum. Subsequently, theconcentrated MAO/metallocene solution was slowly added dropwise at 25°C. to a suspension of 5.0 g of the MAO-laden silica gel prepared asdescribed above in 250 ml of iso-decane over a period of 4 hours. After1 hour, the supported catalyst was isolated by filtration, washed with2×20 ml of pentane and dried at 25° C. in a stream of N₂. The yield was6.4 g.

10.2 Polymerization

The polymerization was carried out using a method similar to Example1.2. In the polymerization of propylene, 98 mg of supported catalystgave 850 g of polymer powder, corresponding to a productivity of 8150 gof PP/g of catalyst/h. The associated polymer data are listed in Table3.

Example 11

11.1 Preparation of the catalyst

20 g of silica gel SG 332 were partially dehydrated at 180° C. underreduced pressure for 8 hours and slowly added to 160 ml of 1.53M MAO(toluene solution) at such a rate that the temperature did not exceed35° C. Subsequently, 200 ml of n-decane were added dropwise to thesilica gel/MAO/toluene suspension over a period of 4 hours and themixture was stirred at 35° C. for a further 4 hours. The supernatantcolorless solution was then filtered off and the MAO-laden support waswashed with 2×50 ml of toluene and subsequently with 2×50 ml of pentane.Drying at 25° C. in a stream of N₂ gave 27.5 g of MAO-laden silica gel.5.0 g of the MAO-laden silica gel thus prepared were admixed at 35⁰cwith a solution of 288 mg ofrac-bis[3,3′-(2-methylbenzo[e]indenyl)]dimethylsilanediylzirconiumdichloride in 65 ml of 1.53M MAO (toluene solution). 200 ml of n-decanewere added dropwise over a period of 4 hours and after 1 hour thesupported catalyst was isolated by filtration, washed with 2×20 ml ofpentane and dried at 25° C. in a stream of N₂. The yield was 5.5 g.

11.2 Polymerization

The polymerization was carried out using a method similar to Example1.2. In the polymerization of propylene, 204 mg of supported catalystgave 1095 g of polymer powder, corresponding to a productivity of 5100 gof PP/g of catalyst/h. The associated polymer data are listed in Table3.

Example 12

5.0 g of MAO-laden support material as described in Example 11.1 weresuspended at 250C in a solution of 288 mg ofrac-bis[3,3′-(2-methylbenzo[e]indenyl)]dimethylsilanediylzirconiumdichloride in 65 ml of 1.53M MAO solution in toluene (Witco, toluenesolution) and, after addition was complete, admixed dropwise with 100 mlof n-decane. After a further hour at 25° C., the toluene wasfractionally distilled off at 35° C. in a high vacuum. The remainingsuspension was filtered, the solid was washed with 2×20 ml of pentaneand dried in a stream of N₂. The yield was 5.8 g.

The polymerization was carried out using a method similar to Example1.2. In the polymerization of propylene, 395 mg of supported catalystgave 860 g of polymer powder, corresponding to a productivity of 2050 gof PP/g of catalyst/h. The associated polymer data are listed in Table3.

Example 13

The procedure of Example 11 was repeated, but a solution of PMAO, 20%strength by weight in toluene (manufactured by Akzo, Deventer, TheNetherlands) was used in place of the MAO solution for supporting thecatalyst. Correspondingly less 20% strength PMAO/toluene solution wasused here in order to use the same molar amounts. The yield of supportedcatalyst was 5.6 g.

The polymerization was carried out using a method similar to Example1.2. In the polymerization of propylene, 207 mg of supported catalystgave 1140 g of polymer powder, corresponding to a productivity of 5250 gof PP/g of catalyst/h. The associated polymer data are listed in Table3.

Example 14

The procedure of Example 12 was repeated, but the supported catalyst wasprepared using 20% strength by weight PMAO (toluene solution).Correspondingly less PMAO/toluene solution was used here in order to usethe same molar amounts. The yield was 5.7 g.

The polymerization was carried out using a method similar to Example1.2. In the polymerization of propylene, 413 mg of supported catalystgave 920 g of polymer powder, corresponding to a productivity of 2100 gof PP/g of catalyst/h. The associated polymer data are listed in Table3.

Example 15

The procedure of Example 13 was repeated, but the support material andthe supported catalyst were prepared using a 30% strength by weight MAOsolution in toluene. Correspondingly less of this MAO/toluene solutionwas used here in order to use the same amounts of MAO. The yield ofsupported catalyst was 5.5 g.

The polymerization was carried out using a method similar to Example1.2. In the polymerization of propylene, 413 mg of supported catalystgave 920 g of polymer powder, corresponding to a productivity of 2100 gof PP/g of catalyst/h. The associated polymer data are listed in Table3.

Example 16

The procedure of Example 14 was repeated, but the support material andthe supported catalyst were prepared using a 30% strength by weightMAO/toluene solution as in Example 15. Correspondingly less 30% strengthby weight MAO/toluene solution was used here in order to use the sameamounts of MAO. The yield of supported catalyst was 5.6 g.

The polymerization was carried out using a method similar to Example1.2. In the polymerization of propylene, 443 mg of supported catalystgave 920 g of polymer powder, corresponding to a productivity of 1900 gof PP/g of catalyst/h. The associated polymer data are listed in Table3.

Example 17

17.1 Preparation of the catalyst

20 g of aluminum oxide (ICN Alumina A, Act. I, ICN-Biomedicals,Eschwege) were suspended in 200 ml of n-decane and 160 ml of 1.53M MAO(witco, toluene solution) were then slowly added dropwise at 25° C. overa period of 4 hours. After 12 hours at 25° C., the supernatant colorlesssolution was filtered off and the MAO-laden support was washed with 2×50ml of toluene and subsequently with 2×50 ml of pentane. Drying at 25° C.in a stream of N₂ gave 28.9 g of MAO-laden aluminum oxide. 5.0 g of theMAO-laden aluminum oxide thus prepared were suspended in a solution of145 mg ofrac-bis[3,3′-(2-methylbenzo[e]indenyl)]dimethylsilanediylzirconiumdichloride and 35 ml of 1.53M MAO (toluene solution) and cooled to 0° C.in 5° steps over a period of 4 hours. 250 ml of n-decane was then addeddropwise at 0° C. After 1 hour, the supported catalyst was isolated byfiltration, washed with 2×20 ml of pentane and dried at 25° C. in astream of N₂. The yield was 5.5 g.

17.2 Polymerization

A dry 10 l autoclave which had been flushed with nitrogen was chargedwith 50 g of polypropylene powder. Subsequently, 4 l of liquidpropylene, 10 ml of triisobutylaluminum (2M in heptane) and 504 mg ofcatalyst were introduced one after the other into the reactor via alock. At a stirrer speed of 350 rpm, the autoclave was charge at 25° C.with a further 3 l of propylene. The temperature was subsequentlyincreased stepwise to 65° C., with an internal pressure of 26 bar beingestablished. Polymerization was carried out at 65° C. for 60 minutes andthe polymer was discharged in a stream of nitrogen. This gave 910 g ofpolypropylene, corresponding to a productivity of 1700 g of PP/g ofcatalyst/h. The associated polymer data are listed in Table 3.

Example 18

The preparation of the support material was carried out using a methodsimilar to Example 6, but the support material was prepared on the basisof aluminum oxide (ICN Alumina A, Act. I) with the iso-dodecane beingreplaced by n-decane. 5.0 g of the MAO-laden support material thusprepared was suspended at 25° C. in a solution of 145 ml ofrac-bis[3,3′-(2-methylbenzo[e]indenyl)]dimethylsilanediylzirconiumdichloride and 35 ml of 1.53M MAO (toluene solution). 250 ml of n-decanewere added dropwise at 25° C. over a period of 4 hours. After 1 hour,the toluene present was distilled off at 25° C. in a high vacuum. Theremaining suspension was filtered, the solid was washed with 2×50 ml ofpentane and dried in a stream of N₂. The yield was 5.8 g.

The polymerization was carried out using a method similar to Example 17.In the polymerization of propylene, 751 mg of supported catalyst gave640 g of polymer powder, corresponding to a productivity of 850 g ofPP/g of catalyst/h. The associated polymer data are listed in Table 3.

Example 19

19.1 Preparation of the catalyst

250 g of silica gel SG 332 were partially dehydrated at 180° C. underreduced pressure for 8 hours, suspended in 250 ml of iso-dodecane and 2l of 1.53M MAO (toluene solution) were then slowly added dropwise at 25°C. over a period of 8 hours. After 12 hours at 25° C., the supernatantcolorless solution was filtered off and the MAO-laden support was washedwith 3×1 l of toluene and subsequently with 2×1 l of iso-dodecane. TheMAO-laden silica gel was resuspended in 4.5 l of iso-dodecane andadmixed with a solution of 11.69 g ofrac-bis[3,3′-(2-methylbenzo[e]indenyl)]dimethylsilanediylzirconiumdichloride in 2.63 1 of 1.53M MAO (toluene solution) over a period of 8hours. After 1.5 hours, the supported catalyst was isolated byfiltration, washed with 2×1 l of pentane and dried at 25° C. in a streamof N₂. The yield was 385 g.

19.2 Polymerization in a continuous 200 l gas-phase reactor

The polymerization was carried out in a vertically mixed gas-phasereactor having a utilizable capacity of 200 1. The reactor contained anagitated fixed bed of finely divided polymer. The reactor output was inall cases 20 kg of polypropylene per hour.

Liquid propylene was decompressed into the gas phase reactor at 60° C.at a pressure of 24 bar. Polymerization was carried out continuously ata mean residence time of 2.5 hours using the catalyst system described.The catalyst was metered in together with the propylene added forregulating the pressure. The amount of catalyst metered in was such thatthe mean output of 20 kg/h was maintained. Triisobutylaluminum waslikewise metered in in an amount of 30 mmol/h as a 1 molar solution inheptane. Polymer was gradually removed from the reactor via an immersedtube by brief depressurization of the reactor. The productivity wascalculated from the silicon content of the polymers using the formulabelow:

P═Si content of the catalyst/Si content of the product

The process parameters and characteristic product properties are shownin Table 4.

Example 20

The preparation of the catalyst was carried out using a method similarto Example 19 and the polymerization was carried out in the continuous200 l gas-phase reactor using a method similar to Example 19.2, withhydrogen being added as molecular weight regulator. The hydrogenconcentration in the reaction gas was 0.08% by volume and was determinedby gas chromatography.

The process parameters and characteristic product properties are shownin Table 4.

Example 21

The preparation of the catalyst and the polymerization in the continuous200 l gas-phase reactor were carried out using a method similar toExample 20. The hydrogen concentration in the reaction gas was 0.115% byvolume and was determined by gas chromatography.

The process parameters and characteristic product properties are shownin Table 4.

Example 22

22.1 Preparation of the catalyst

10 g of spray-dried silica gel (particle diameter: 20-45 μm; specificsurface area: 325 m²/g; pore volume: 1.50 cm³/g) were dehydrated underreduced pressure at 180° C. for 8 hours, then suspended in 40 ml oftoluene and subsequently admixed at 25° C. with 78 ml of 1.53 Mmethylaluminoxane (toluene solution). After 12 hours, 150 ml ofiso-dodecane were slowly added over a period of 4 hours and the mixturewas stirred further for 1.5 hours at 25° C. The silica gel which hadbeen deactivated with methylaluminoxane was subsequently filtered off,washed twice with 20 ml each time of toluene and twice with 20 ml eachtime of pentane and dried in a nitrogen-fluidized bed.

The MAO-laden silica gel was added to a mixture of 525 mg ofbis[3,3′-(2-methylbenzo[e]indenyl)]dimethylsilanediylzirconiumdichloride and 120 ml of 1.53 M methylaluminoxane solution (in toluene)and stirred at 25° C. After 20 hours, 250 ml of iso-dodecane were slowlyadded over a period of 4 hours and the mixture was stirred further for1.5 hours. The solid was subsequently filtered off, washed twice with 20ml each time of pentane and dried in a nitrogen-fluidized bed. The yieldof supported catalyst was 16.8 g.

2.2 Polymerization of propylene

The polymerization was carried out using a method similar to Example1.2. In the polymerization, 84 mg of supported catalyst gave 1100 g ofpolymer powder, corresponding to a productivity of 12 500 g of PP/g ofcatalyst/h.

TABLE 1 Properties of polymers obtained Exam- Exam- Exam- Exam- Exam-ple 1 ple 2 ple 3 ple 4 ple 5 Bulk density [g/l] 427 438 418 385 390Flowability 40.5 40.5 41.5 42.0 42.5 R 20 [g/sec] Sieve analysis: <0.1mm [%] 0.0 0.1 0.2 0.0 0.0 0.1 mm-0.5 mm [%] 0.2 0.8 1.5 0.4 0.5 0.25mm-0.5 mm [%] 7.0 11.6 4.3 1.4 1.8 0.5 mm-1.0 mm [%] 72.5 68.5 30.1 14.78.7 1.0 mm-2.0 mm [%] 20.0 18.2 62.9 83.0 88.1 >2.0 mm [%] 0.3 0.8 1.00.5 0.9

TABLE 2 Results of the polymerization experiments Example 1 Example 2Example 3 Example 4 Example 5 Productivity [g of poly- 1 500 2 450 3 7004 950 5 950 mer/g of catalyst/h] Activity [g of polymer/ 214 286 180 147151 639 137 119 123 444 mmol of Zr/h] Zr content 7.0 13.6 24.4 36.1 48.2[μmol of Zr/g of catalyst] Al content 14.3 14.8 14.9 15.0 16.8 [% byweight] [Al]/[Zr] ratio 757 403 226 154 129 XS [% by weight]* 0.6 0.30.3 0.4 0.6 MFI [g/10 min]** 4.4 5.7 4.6 4.7 4.0 Viscosity η[dl/g] 2.282.09 2.17 2.17 2.67 Melting point (DSC) [° C.] 146.7 143.6 146.3 146.3145.4 M_(w) [g/mol] 295 027 246 368 276 562 288 197 331 045 M_(w)/M_(n)2.0 1.8 1.7 1.9 1.9 *XS = xylene-soluble proportion in accordance withISO 1873-1: 1991 (E) **MFI = Melt Flow Index in accordance with DIN ISO1133, Method B at 230° C./2.16 kg

TABLE 3 Results of the polymerization experiments Example 6 Example 7Example 8 Example 9 Example 10 Productivity [g of poly- 5 050 5 700 5000 5 300 8 150 mer/g of catalyst/h] XS [% by weight] 0.3 0.6 0.4 0.50.3 MFI [g/10 min] 5.6 5.8 5.9 3.7 7.2 Viscosity η[dl/g] 2.15 2.14 2.012.12 2.14 Example 11 Example 12 Example 13 Example 14 Example 15Productivity [g of poly- 5 100 2 050 5 200 2 100 4 550 mer/g ofcatalyst/h] XS [% by weight] 0.5 0.3 0.4 0.6 0.1 MFI [g/10 min] 6.1 4.35.8 8.93 7.17 Viscosity η[dl/g] 2.13 2.18 2.10 1.93 2.02 Example 16Example 17 Example 18 Example 22 Productivity [g of poly- 1 900 1 700850 12 500 mer/g of catalyst/h] XS [% by weight] 0.8 0.6 0.6 0.4 MFI[g/10 min] 3.6 5.3 5.3 2.9 Viscosity η[dl/g] 2.29 2.12 2.12 2.37

TABLE 4 Influence of hydrogen on the polymerization Example 19 Example20 Example 21 p/T [bar/° C.] 24/60 24/60 24/60 TIBA* [mmol/h] 30 30 30H₂ [% by volume] 0 0.08 0.115 MFI [g/10′] 4.8 9.1 21.6 DSC [° C.] 146.2145.9 146.3 eta [gl/g] 2.15 1.81 1.58 XS [%] 0.4 0.5 0.5 Si [ppm] 45.630.2 29.2 P [g of PP/g of cat] 5700 8600 8900 R20* [g/sec] 41.7 45.5 40Bulk density [g/l] 353 405 375 d′[mm] 1.34 1.35 1.38 <0.125 mm [%] 0.010.04 0.04 <0.25 mm [%] 0.3 0.57 0.6 <0.50 mm [%] 2.22 4.02 4.73 <1.0 mm[%] 35.78 34.16 31.17 <2.0 mm [%] 61.2 58.53 59.75 >2.0 mm [%] 0.49 2.683.71 *TIBA = Triisobutylaluminum *R20 = Flowability in accordance withDIN 53492 (1992), ISO 6186 (1980)

We claim:
 1. A process for preparing supported transition metal catalystcomprising a particulate organic or inorganic support material, atransition metal complex and a compound capable of forming metalloceniumions, which comprises the following process steps: a) contacting asolution of a compound capable of forming metallocenium ions with asecond solvent in which this compound is only sparingly soluble, in thepresence of the support material, b) removing at least part of thesolvent from the support material and c) contacting a solution of amixture of a compound capable of forming metallocenium ions and atransition metal complex of the general formula III

 where the substituents have the following meanings: M is titanium,zirconium, hafnium, vanadium, niobium or tantalum, X is fluorine,chlorine, bromine, iodine, hydrogen, C₁-C₁₀-alkyl, C₆ -C₁₅-aryl,alkylaryl having from 1 to 10 carbon atoms in the alkyl radical and from6 to 20 carbon atoms in the aryl radical, —OR⁷ or —NR⁷R⁸,  where R⁷ andR⁸ are C₁-C₁₀-alkyl, C₆-C₁₅-aryl, alkylaryl, arylalkyl, fluoroalkyl orfluoroaryl each having from 1 to 10 carbon atoms in the alkyl radicaland from 6 to 20 carbon atoms in the aryl radical, R² to R⁶ arehydrogen, C₁-C₁₀-alkyl, 5- to 7-membered cycloalkyl which may in turnbear a C₁-C₁₀-alkyl group as substituent, C₆-C₁₅-aryl or arylalkyl,where two adjacent radicals may also together form a saturated orunsaturated cyclic group having from 4 to 15 carbon atoms, or Si(R⁹)₃where R⁹ is C₁-C₁₀-alkyl, C₃-C₁₀-cycloalkyl, or C₆-C₁₅-aryl,

 where the radicals R¹⁰ to R¹⁴ are hydrogen, C₁-C₁₀-alkyl, 5- to7-membered cycloalkyl which may in turn bear a C₁-C₁₀-alkyl group assubstituent, C₆-C₁₅-aryl or arylalkyl and where two adjacent radicalsmay also together form a saturated or unsaturated cyclic group havingfrom 4 to 15 carbon atoms, or Si(R¹⁵)₃ where R¹⁵ is C₁-C₁₀-alkyl,C₆-C₁₅aryl or C₃-C₁₀-cycloalkyl, or where the radicals R⁵ and R¹³together form a group —R¹⁶—, where

═BR¹⁷, ═AlR¹⁷, —Ge—, —Sn—, —O—, —S—, ═SO, ═SO₂ ═NR¹⁷, ═CO, ═PR¹⁷ or═P(O)R¹⁷,  where R¹⁷, R¹⁸, and R¹⁹ are identical or different and arehydrogen, halogen, C₁-C₁₀-alkyl, C₆-C₁₀-alkyl, C₁-C₁₀-fluoroalkyl,C₆-C₁₀-fluoroaryl, C₆-C₁₀-aryl, C₁-C₁₀-alkoxy, C₂-C₁₀-alkenyl,C₇-C₄₀-arylalkyl, C₈-C₄₀-arylalkenyl or C₇-C₄₀-alkylaryl or two adjacentradicals together with the atoms connecting them from a ring, and M² issilicon, germanium or tin, with a second solvent in which this mixtureis only sparingly soluble, in the presence of the support materialobtained as described in a) and b).
 2. A process as claimed in claim 1,wherein the compound capable of forming metallocenium ions which is usedcomprises open-chain or cyclic aluminoxane compounds of the generalformula I or II

where R¹ is C₁-C₄-alkyl and m is an integer from 5 to
 30. 3. A processas claimed in claim 1, wherein the transition metal complexes used areones having benzindenyl ligands.
 4. A process as claimed in claim 1,wherein the transition metal complexes contain two aromatic ring systemsbridged to one another as ligands.
 5. A process as claimed in claim 1,wherein, in process step b), at least part of the solvent is removed byfiltration of the support material.
 6. A process as claimed in claim 1,wherein, in process step b), at least part of the solvent is removed bydistillation.
 7. A process as claimed in claim 1, wherein the supportmaterial is, before the process step c), washed with a solvent in whichthe compound capable of forming metallocenium ions is readily soluble.8. A supported catalyst obtained by a process claimed in claim
 1. 9. Aprocess for preparing polymers of C₂-C₁₂-alk-1-enes at from −50 to 300°C. and pressures of from 0.5 to 3000 bar in the presence of a catalystas claimed in claim 8.